Method of loading fin stabilized ammunition



Feb. 14, 1961 G. c. POTTS METHOD OF LOADING FIN STABILIZED AMMUNITION ial6 Filed March 26, 1959 FIGZ.

FIG. 7:

FIGS.

ch 0. o 0 00 0 0 0 INVENTOR. GEORGE o. POTTS ATTORNEYS:

METHOD OF LOADING FIN STABILIZED AMMUNITION George C.Potts,,'Philadelphia, Pa., assignor to the United States of America asrepresented by the Secretary of the Army The invention described hereinmay be manufactured and used by or for theGovernment for governmental Ipurposes without the payment to me of any royalty thereon.

This invention relates to a new method of loading finstabilizedammunition.

Heretofore, the loading of tin-stabilized ammunition has been achievedby inserting the propellant through a loading hole located in the baseof the cartridge case. After loading, the hole is closed by a metalplug.

As a result of providing for the loading hole a comparatively thin metalweb exists in the base of the cartrldge case between the loading holeand the side wall. Upon firing of the round this thin web distorts dueto thermal expansion and impact, allowing propelling gases to escapearound the metal plug and producing expansion of the side wall of thecartridge case sufiicient to cause the case to stick in the gun. Thusthe probability of flashback is greatly increased (which would beextremely dangerous, for example when the gun is mounted on a tank), andthe case must be rammed out of the gun after each round is fired.

It is the object of this invention to overcome the above difiiculties,eliminate the cost of machining the loading hole and the mating plug,and materially reduce the time and tedium of loading by elimination ofthe loading hole entirely. This is accomplished by first partiallyloading the cartridge case with propellant and then adding the remainderof the propellant later while pressing the projectile into place asdescribed hereinafter. More precisely the invention comprises apropellant supporting cylinder for a fin-stabilized projectile incombination with a cup washer and a back-up plate, to contain thepropellant around the projectile, between the sabot and the stabilizingfins, while the projectile is pressed into the cartridge case and seatedon the bed of propellant previously loaded into the case.

The invention can best be understood by reference to the figures inwhich:

Fig. l is a partial sectional view of a cartridge case with the primerin place;

Fig. 2 is the same view with the body of the cartridge case partiallyfilled with propellant;

Fig. 3 is a partial sectional view of the fin-stabilized projectile inthe propellant supporting cylinder, with the cup washer placed over thefins;

Fig. 4 is a top plan view showing the cup washer in place within thepropellant supporting cylinder shown in Fig. 3;

Fig. 5 is a partial view of the propellant supporting cylindercontaining the projectile and propellant, with the cup washer andback-up plate in position;

Fig. 6 is a partial sectional view of the cartridge case with thecylinder, containing the projectile and propellant, positioned at themouth of the cartridge case, immediately preceding the projectile beingpressed into place;

Fig. 7 shows the completed assembly with the pro- 2,971,426 PatentedFeb. 14, 1961 jectile fully seated on the previously prepared propellantbed.

The cartridge case, as shown in Fig. 1, consists of three sections; amouth section 10, a tapered neck section 11, and a body section 12; Theprimer 13 is contained within the body of the cartridge case.

The first step in loading the cartridge case, shown in Fig. 2, isfilling the body portion with propellant 9, up to a height determined bythe rear end of the stabilizing fins of a projectile when the projectileis inserted within the cartridge case. i

The second step shown in Fig; 3 is placing the projectile 14 and sabot15 in a propellant supporting cylinder 18, with the stabilizing fins 16of the projectile being uppermost. An open-based retaining cup washer19, having hinged slit side walls 20, is placed over the rear end of thestabilizing fins, so that the hinged slit side walls extendlongitudinally between the stabilizing fins and the propellantsupporting cylinder. Fig. 4 is a view looking downward at the cup washerin place within the propellant supporting cylinder.

The third step shown in Fig. 5 consists of pouring propellant 9 throughthe open base of the retaining cup washer to fill the supportingcylinder with propellant around the boom 17 and the stabilizing fins ofthe projectile, between the sabot and the rear end of the stabilizingfins. A back-up plate 21 is then secured to the rear end of thestabilizing fins, thereby closing the open base of the cup washer andholding the cup washer and propellant in place.

The fourth step shown in Fig. 6 is inverting the cylinder containing theprojectile, propellant, retaining cup washer, and back-up plate, andpositioning it at the mouth of the partially-filled cartridge case Theprojectile is then pressed into place within the cartridge case,carrying the propellant from within the cylinder into the cartridge casewith it, and leaving the cylinder empty. As the rear end of theprojectile moves from the mouth portion of the cartridge case into thetapered neck section, the hinged sidewalls of the cup washer spreadoutwardly to continue to contain the propellant around the projectileand prevent the propellant from tumbling out and interfering with thecomplete seating of the projectile on the previously prepared bed ofpropellant.

Fig. 7 shows the projectile fully seated within the substantially competely filled cartridge case and the empty supporting cylinder removed.As an example of the problems involved, one might use a cartridge casefor a mm. projectile. Heretofore the cartridge case, having a basediameter of approximately 6 inches, had a loading hole of approximately1% inches machined in the base between the primer pocket and the sidewall of the case. Propellant, having a web size of about 0.070 inch(0.930 inch long by 0.327 in diameter), was then inserted through theloading hole to fill up the case around the projectile. The loading holewas then closed by inserting a machined plug.

As a result of this invention the loading time of the above cartridgecase was reduced to approximately onethird of what it had been, and thenecessity for machining the loading hole and plug, with its attendantcost and weakening of the case, were obviated. This was accomplished bymaking use of a cup washer having a base diameter of 3 /8 inches, and aback-up plate, having a diameter of 3% inches, fastened over'the cupwasher. The backup plate was perforated to allow the flame to go throughiteasily, and the cup washer and the back-up plate were both fabricatedfrom 0.010 paper stock.

I claim:

A process for filling a cartridge case for a projectile havingstabilizing fins and a sabot, said process comprising: partially fillingsuch a cartridge case with its base lowermost with the propellant to aheight contiguous stabilizing fins of a projectile when later inserted;placing a propellant supporting cylinder around a projectile with itsfins uppermost and with said cylinder extending longit-ndinallybetwee'nthe stabilizing fi'ns and the, sabot for the purpose of retainingpropellant around the projectile until said projectile with propellantis later enclosed and held by the cartridge case; placinga retaining cupwasher having an open base and hinged split sides over a rear end of thestabilizing fins, so that the slit sides extend longitudinally betweenthe -fins and the propellant supporting cylinder; loading propellantthrough the open base of saidretainingcup washer to fill said cylinderbetween said sabot and said cup washer, said sabot retaining thepropellant after it is loaded into the-supporting cylinder around theprojectile; securing a back-up plate to the rear end of the stabilizingfins and closing the base of said cup washer, to prevent the propellantfrom falling out when the supporting cylinder and projectile areinverted; inverting the propellant supporting cylinder and projectile;positioning said cylinder and projectile at the mouth of the cartridgecase preparatory to pressing the projectile with propellant into thecartridge case; pressing the projectile and propellant out of thesupporting cylinder and into the partially filled cartridge case untilsaid back-up plate, which is substantially coincident with the rear endof the stabilizing fins, is contiguous the top of the propellant in thepartially filled cartridge case, the said hinged slit sides of said cupwasher having spread outwardly due to the weight of the propellant, tocontinue to contain the propellantas the projectile moves into anenlarged throat portion of said cartridge case; and. withdrawing thesupporting cylinder rfrom the mouth of the cartridge case, leavingthepropellantsubstantially filling a space within the cartridge casearound the projectile, between the base of the cartridge case and the'sabot.

References Cited in the file of this patent UNITED PATENTS

